UploadPack: support custom packfile-to-URI mapping

Teach UploadPack to take a provider of URIs corresponding to cached
packs. When fetching, if the client supports the packfile-uri feature,
and if such a cached pack were to be streamed, instead send the
corresponding URI.

This packfile-uri feature is implemented in the jt/fetch-cdn-offload
branch of Git. There is interest in this feature [1], but it is not yet
merged.

[1] https://public-inbox.org/git/cover.1552073690.git.jonathantanmy@google.com/

Change-Id: I9a32dae131c9c56ad2ff4a8a9638ae3b5e44dc15
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
index 22c67c1013..528a63f9c0 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
@@ -35,6 +35,8 @@ import org.eclipse.jgit.internal.storage.dfs.DfsGarbageCollector;
 import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
 import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
 import org.eclipse.jgit.internal.storage.file.PackLock;
+import org.eclipse.jgit.internal.storage.pack.CachedPack;
+import org.eclipse.jgit.internal.storage.pack.CachedPackUriProvider;
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
@@ -2150,6 +2152,58 @@ public class UploadPackTest {
 	}
 
 	@Test
+	public void testV2FetchPackfileUris() throws Exception {
+		// Inside the pack
+		RevCommit commit = remote.commit().message("x").create();
+		remote.update("master", commit);
+		generateBitmaps(server);
+
+		// Outside the pack
+		RevCommit commit2 = remote.commit().message("x").parent(commit).create();
+		remote.update("master", commit2);
+
+		server.getConfig().setBoolean("uploadpack", null, "allowsidebandall", true);
+
+		ByteArrayInputStream recvStream = uploadPackV2(
+			(UploadPack up) -> {
+				up.setCachedPackUriProvider(new CachedPackUriProvider() {
+					@Override
+					public PackInfo getInfo(CachedPack pack,
+							Collection<String> protocolsSupported)
+							throws IOException {
+						assertThat(protocolsSupported, hasItems("https"));
+						if (!protocolsSupported.contains("https"))
+							return null;
+						return new PackInfo("myhash", "myuri");
+					}
+
+				});
+			},
+			"command=fetch\n",
+			PacketLineIn.DELIM,
+			"want " + commit2.getName() + "\n",
+			"sideband-all\n",
+			"packfile-uris https\n",
+			"done\n",
+			PacketLineIn.END);
+		PacketLineIn pckIn = new PacketLineIn(recvStream);
+
+		String s;
+		// skip all \002 strings
+		for (s = pckIn.readString(); s.startsWith("\002"); s = pckIn.readString()) {
+			// do nothing
+		}
+		assertThat(s, is("\001packfile-uris"));
+		assertThat(pckIn.readString(), is("\001myhash myuri"));
+		assertTrue(PacketLineIn.isDelimiter(pckIn.readString()));
+		assertThat(pckIn.readString(), is("\001packfile"));
+		parsePack(recvStream);
+
+		assertFalse(client.getObjectDatabase().has(commit.toObjectId()));
+		assertTrue(client.getObjectDatabase().has(commit2.toObjectId()));
+	}
+
+	@Test
 	public void testGetPeerAgentProtocolV0() throws Exception {
 		RevCommit one = remote.commit().message("1").create();
 		remote.update("one", one);